Motion transmittal and sealing means therefor



Jan. "19, 1954 c s 2,666,658

MOTION TRANSMITTAL AND SEALING MEANS THEREFOR Filed Oct. 19, 1949 INVEN TOR.

How/Q0 H AUC/(S FITTORNE) partially solved by use of a stuffing box.

Patented Jan. 19, 1954 MOTION TRANSMITTAL AND SEALING MEANS THEREFOR Howard H. Laucks, Boonton, N; J., assignor to V Bendix Aviation Corporation, Teterboro, N. .L,

a corporation of Delaware Application October 19, 1949, Serial No. 122,159

1 Claim. (01. 286-1) The present invention relates to motion indicating means and sealing means for the same.

One of the problems in the design and construction of equipment such as servos, valves, motors or the like, wherein a movable member reciprocates or rotates in a high pressure chamber, is to devise a means of transmitting values referable to said member outside said chamber and to adequately seal said means.

In certain applications, this problem has beer;

Bu this solution tends to impose frictional load upon the rod, and further difiiculty is encountered in providing an absolute seal where the shaft is rotating or sliding.

The present invention contemplates providing a very small diameter tube with a relatively long length. Within this tube is a close fitting wire. High pressure oil at the chamber end of the tube is thus confronted with a very long leakage path of small cross-sectional area. Due to the small clearance present, the wire would be free to move in the tube, thereby relaying a motive signal.

It is, therefore, one of the objects of the present invention to provide means for transitting motion from a movable member in a high pressure chamber to a position indicating device outside said chamber and to do so in a novel and effective manner.

Another object of the invention is to provide reliable'sealing means for the foregoing motion transmitting means.

Another object of the invention is to provide a seal of the above-indicated nature which will permit a certain amount of dimensional variation between the moving member and its guiding surfaces.

Still another object of the invention is to provide motion transmitting means and sealing means therefor that will be simple, easy and economical to manufacture, maintain and install, and yet positive and reliable in operation.

The foregoing and other objects and advantages will appear more fully hereinafter from a consideration of the detailed description which follows, taken together with the accompanying drawing wherein one embodiment of the invention is illustrated by way of example. It is to be expressly understood, however, that the drawing is for the purposes of illustration only and is not to be construed as defining the limits of the invention.

Referring to the drawings, wherein like reference characters designate like parts,

The figure is an elevation view in section of a typical device incorporating the invention.

In the single figure drawing, a casing H! as of a valve, servo, pump or the like encompasses a fluid filled high pressure chamber :2 wherein a movable member I 4 reciprocates. The pressure chamber I2 is sealed off at one end by means of a closure plug, or end wall, 16 that is held in place by the pins [8 and 26. A thru hole, or bore, 22 in the closure plug l6 leads into a larger diameter hole, or bore, 23 through the plug I6 and the pins l8 and 20, and communicates with the pressure chamber l2. A thin walled and relatively long tube 24 is firmly cantilevered into the hole 22, and extends to the end of hole 23 in the plug I6. Within said tube 24 a very close fitting wire 26 is passed and secured at one end as at boss 28 to the movable member 14. The opposite end 30 of the wire 26 leads to some position indicating device not shown here, common to the art, such as a gage, counter, or the like.

Having thus described the invention, it will now be apparent to those skilled in the art that when the reciprocating member M moves, it will transmit said movement to the wire 26 outside of the high pressure chamber [2 immediately and without loss in magnitude, to said indicating device to give indicia referable to the moving member l4.

Although the wire 26 fits snugly within the tube 24, a minimum amount of clearance therebetween is nevertheless present. Said minimum clearance between the wire 26 and the tube 24 affects a reliable seal since the fluid in the high pressure chamber I2 is confronted with a relatively long leakage path of negligible cross-sectional area and thereby finds itself effectively trapped.

It is particularly to be noted that since the tube 24 is secured at the cantilevered end only, a certain amount of flexibility therein will be available at the other end in proximity to the chamber I2. Said flexibility will suffice to permit a reasonable amount of dimensional misalignment between the point at which the wire is secured to the moving member l 4, and the point at which the wire protrudes through the closure plug l6.

There are thus provided simple and efiective means for transmitting motion from a movable member in a high pressure chamber to a position indicating device outside that chamber that are adequately sealed, and which do not penalize the moving member with frictional loads.

Although only a single embodiment and application of the invention has been illustrated and described, other changes and modifications in the form and relative arrangements of parts which will be apparent to those skilled in the tube being circumferentially spaced; from the walls of the through bore throughout its unsecured length, a wire connected at one end, to,

said movable member and extending through said tube, said tube and Wire having a minimum 3 amount of clearance therebetween to define a relatively long path of negligible cross-sectional area along the length of said tube between said pressure chamber and the exterior thereof and wherein the pressurized fluid is trapped to therebyseaL said pressure chamber;

HOWARD H. LAUCKS.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 72,340 Turner Dec. 1'7, 1867 I 13565907 Hicks et a1 June 28, 1932 2 ,307,575 Davis Jan. 5, 1943 V FOREIGN PATENTS Number Country Date 3735491 Great Britain May 26, 1932 

